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#include <math.h>
#include <jni.h>
#include <android/bitmap.h>
#include "SkCanvas.h"
#include "SkGraphics.h"
#include "SkSurface.h"
#include "SkString.h"
#include "SkTime.h"
/**
* Draws something into the given bitmap
* @param env
* @param thiz
* @param dstBitmap The bitmap to place the results of skia into
* @param elapsedTime The number of milliseconds since the app was started
*/
extern "C"
JNIEXPORT void JNICALL Java_com_example_HelloSkiaActivity_drawIntoBitmap(JNIEnv* env,
jobject thiz, jobject dstBitmap, jlong elapsedTime)
{
// Grab the dst bitmap info and pixels
AndroidBitmapInfo dstInfo;
void* dstPixels;
AndroidBitmap_getInfo(env, dstBitmap, &dstInfo);
AndroidBitmap_lockPixels(env, dstBitmap, &dstPixels);
SkImageInfo info = SkImageInfo::MakeN32Premul(dstInfo.width, dstInfo.height);
// Create a surface from the given bitmap
SkAutoTUnref<SkSurface> surface(SkSurface::NewRasterDirect(info, dstPixels, dstInfo.stride));
SkCanvas* canvas = surface->getCanvas();
// Draw something "interesting"
// Clear the canvas with a white color
canvas->drawColor(SK_ColorWHITE);
// Setup a SkPaint for drawing our text
SkPaint paint;
paint.setColor(SK_ColorBLACK); // This is a solid black color for our text
paint.setTextSize(SkIntToScalar(30)); // Sets the text size to 30 pixels
paint.setAntiAlias(true); // We turn on anti-aliasing so that the text to looks good.
// Draw some text
SkString text("Skia is Best!");
SkScalar fontHeight = paint.getFontSpacing();
canvas->drawText(text.c_str(), text.size(), // text's data and length
10, fontHeight, // X and Y coordinates to place the text
paint); // SkPaint to tell how to draw the text
// Adapt the SkPaint for drawing blue lines
paint.setAntiAlias(false); // Turning off anti-aliasing speeds up the line drawing
paint.setColor(0xFF0000FF); // This is a solid blue color for our lines
paint.setStrokeWidth(SkIntToScalar(2)); // This makes the lines have a thickness of 2 pixels
// Draw some interesting lines using trig functions
for (int i = 0; i < 100; i++)
{
float x = (float)i / 99.0f;
float offset = elapsedTime / 1000.0f;
canvas->drawLine(sin(x * M_PI + offset) * 800.0f, 0, // first endpoint
cos(x * M_PI + offset) * 800.0f, 800, // second endpoint
paint); // SkPapint to tell how to draw the line
}
// Unlock the dst's pixels
AndroidBitmap_unlockPixels(env, dstBitmap);
}
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